#-*- coding: utf-8 -*-
# ============================================================================
# MIT License
#
# Copyright (c) 2019 hey-yahei
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
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# SOFTWARE.
# ============================================================================

from mxnet import operator, symbol

__all__ = ['FakeSymbol']
__author__ = 'YaHei'


class Fake(operator.CustomOp):
    """ Fake symbol """
    def forward(self, is_train, req, in_data, out_data, aux):
        pass

    def backward(self, req, out_grad, in_data, out_data, in_grad, aux):
        pass


@operator.register("_fake")
class FakeProp(operator.CustomOpProp):
    """ Fake symbol """
    def __init__(self, name="", _in_num=1, _out_num=1, **kwargs):
        super(FakeProp, self).__init__()
        if _out_num is None:
            _out_num = _in_num
        self._in = [f"in{i}" for i in range(int(_in_num))]
        if _out_num == 1:
            print(name)
            self._out = [f"{name}output"]
        else:
            self._out = [f"out{i}" for i in range(int(_out_num))]
        for k, v in kwargs.items():
            self.__setattr__(k, v)

    def list_arguments(self):
        return self._in

    def list_outputs(self):
        return self._out

    def create_operator(self, ctx, in_shapes, in_dtypes):
        return Fake()


def FakeSymbol(*args, _op, **kwargs):
    """ Simple API to create a fake symbol. """
    return symbol.Custom(*args, _op=_op, op_type="_fake", **kwargs)
